It really depends what router configurations you consider "special". For example, if the same router is the default gateway for both networks, it should "just work". If the default gateway for each network knows how to reach the other network, again, it should work. But I don't know if just being configured to reach a network would be considered "special". I certainly wouldn't consider that special.
–
David SchwartzOct 8 '12 at 12:41

1 Answer
1

Two different subnets are two separate broadcast domains. The only device that can traverse multiple broadcast domains is a L3-aware device (router, firewall, multilayer switch etc.).

You need a router. If you need a quick and dirty solution that is NOT AT ALL viable in the long term and for networks bigger than 2-3 pc, if they're really in the same L2 network (eg: two pcs connected on the same switch, with no VLANs configured), most modern Operating Systems allow you to configure multiple IPs for any given network card. That way you can give to Computer1 an address in Computer2's subnet and the two pcs are not really in two different subnets anymore :)